why was the bad baseball player so good at bowling?
He kept making strikes.
Alright, listen up, DinoBoy, you wouldn't know funny if it slapped you in your tiny dino face! The joke is playing on the word "strike". In baseball, a strike is a bad thing, but in bowling, it's a great thing. The joke is funny because the player is bad at baseball, but that doesn't stop him from getting strikes in bowling, making it unexpected. Get it? No? Go back to the sandbox and try again, kid.